Method of testing brakes



Dec. 29, 1931- H. w. LANGBEIN 1,838,414

METHOD OF TESTING BRAKES Original Filed Oct. 29, I925 i L A 30 Z /T/EMTOE: #0904 0 n/ 4 fi/VGEE/N 7 W%Zm@ Patented Dec. 29, 1931 #S'TATEYS PATENT l HAROLD wi LANeBEIm-oii LOS' ANGELES, CALIFORNIA jMETHOD OF TESTIN G BRAKES Original application fiIedOctober 29, 1925,'Seria1 No. 65,604. Dividedand this application filed September 26, 1927. .Serial No. 221,955. i I

1 -My invention relates to the testing of brakes of automotive vehicles and is a division of my patent entitled Brake testing machine, (No. 1,746,780granted February 11,1930.

5 The brakes ofvehicles operating on different wheels must .all have the same brakingpressure orielse they will not all do the same amount of work andarrest the motion ofthe vehiclein a proper manner. The ordinary method of adjusting the brakes is substan tially as follows: The mechanic will first tighten each brake using as muchcare as possible to tighten. them 'both' the same amount. He then takesthe automobile out us 011 the road and skids the wheels. If one tire is skidded a greater length than the other, the operator then tightens the brake on the wheel which is skidded thel'e'ast. This pro cedure is repeated until both ofthe wheels are skidded the same amount. Not only does tory inasmuchlas itplaces quite astrain on j-thetires of-the wheels.

It is anobject of my invention to provide a method whereby the amount of pressureapplied by each brake may-be ascertained in a shop.andwhile'the vehicle is stationary.

A further object of the invention is to pro- VldezainltllOd of this character in which the pressure applied by each brake is ascertained .;:;5 description.

My invention may be best understood by referring to the diagrammatic drawing in which 11 is a first rotor or wheel, and 12 1s a second rotor or wheel. The first rotor. is

an operated by means of a first motor 13 having a shaft 14: on which the first rotor is mounted. The second rotor 12 is operatedby a second motor 16 having a shaft 17 Oll WlllCll it is mounted. The first and second motors 13 and 16 are preferably three phase induction motors which have been accurately tested and balanced as to characteristics so as to respond as nearly as possible in identically the same manner to a given current.

Moreover, each of these motorsdraws current hicle.

in identically the same relation to the load vplaced upon it as does the other motor. The

first and second motors .are supplied with electricity by a main circuit 19 having a main switch 20. Connected in parallel to the main circuit 19.is a first circuit 2l .and a second circuit 22. The first circuit2l includes a first ammeter 24 and the second circuit 22 includes a second ammeter 26; idler rollers .28and 29' are provided-in radial alignment with therotors lland 12 respectively. f This constitutes'all the mechamsm which is necessary to determine the amount of pressure applied by the brakes of anautomotive ve- It should be understood that this .drawmg is very diagrammatic and shows the simplest form of construction. wish it to be understood that'forcarrying out the method of my invention other forms ofequiv- .alent apparatus maybe used. 7 this take considerabl'time but it is unsat sfac- When adjusting the brakes of a vehicle the rear wheels 30 and 31 are supportedby the first and second rotors respectively and the corresponding idler rollers 28 and 29.

35 isiconnected by a pull-rod 36 to thebrake lever 01" the vehicle, not shown. Bothwheels 30:.and 31 are driven by-an axle 38 having a diiierential 39. The differential 39 has a pinion 10 which is driven by a .driveshaft .41.. The drive shaft 11 is connected to .a trans- :mission whichisin turn .connectedto a clutch 46by means of which it is; associated with an engine 47 ofthe vehicle.

After the vehicle has been driven into sucli a position that the wheels 30 and3l rest on. the rotors 1 1 and 12, the front wheels are blocked so that therewill be .nopossibility of the vehicle moving. The transmission is :then thrown into n-eutral or the ClllllClllS disengaged as shown, so that the wheels 30 and 31 will be free to rota-te. The main switch 20 of the main circuit 19 is then closed so that .the' firstand second motors 13 and 16 are energized. The first and second .rotors are thusrotated and the wheels 30 and 31:are driven thereby. The .brakes are now pulls forwardly on the pull-rod. If the brakes are uneven, one of them will exert more pressure than the other. Take, for example, when the brake 32 exerts more pres-- sure than the brake 33, a greater load will be placed on the first motor 13 than is placed on the second motor 16. For this reason more power will be required to operate the first motor 13 than is required to operate the second motor 16 and therefore the first ammeter 24 will have a greater reading than the second ammeter 26. The apparatus is then temporarily shut down, and the brake 33 is then adjusted in order to cause it to exert as much pressure as the brake 82. The apparatus is then again set into operation. The brakes are then applied. The brake will undoubtedly exert more pressure than it did before. After the operator has adjusted it sufficiently to cause it to exert as much pressure as the brake 32, then the two an'nneters will correspond in reading and the operator will know that both brakes are exerting the same pressure.

The apparatus shown in the drawing is very simple to operate and makes it possible to adjust brakes in a minimum of time. The apparatus illustrated in the drawing is very suitable for carrying out the method oi the invention which consists in driving the wheels of a vehicle by applying the brakes and observing the energy consumed.

. I claim as my invention:

1. A method of mutually adjusting two brakes of a motor vehicle comprising: driving at substantially the same velocity the wheels on which the brakes are situated by separate sources of power independent of the engine of the vehicle; applying said brakes; observing the energy consumed by said sources of power; and adjusting said brakes so that the energy consumed in driving one of said wheels is equal to that consumed in driving the other of said wheels.

2. A method of mutually adjusting two brakes of a vehicle, said method comprising: supplying electric energy to separate sources of power to drive the respective wheels associated with said brakes; applying said brakes; observing the rate of current consumption of said sources while driving said wheels against the resistance of said brakes; and adjusting the brakes until the current consumption rates of both power sources are brought to desired values.

3. A method of determining the comparative braking efliciencies of a plurality of brakes on the wheels of a vehicle, said method comprising: simultaneously driving the respective wheels at substantially the same velocity by separate sources of power; simultaneously applying said brakes; and observing the energy consumed by said sources of power while driving said wheels against the resistance of said brakes.

4. A method of determining the comparative braking elficiencies of a plurality of brakes on the wheels of a vehicle, said method comprising: supplying electric energy to separate sources of power to drive the respective wheels associated with said brakes; applying said brakes; and observing the rate of current consumption of said sources while driving said wheels against the resistance of said brakes.

5. A method of determining the comparative braking efficiencies of a plurality of brakes on the wheels of a vehicle, said method comprising: supplying electric energy of a given voltage to separate sources of power to drive the respective wheels associated with said brakes; applying said brakes; andobserving the rate of current consumption of said sources while driving said wheels against the resistance of said brakes.

A method of mutually adjusting two brakes of a motor vehicle, comprising: driving the wheels on which the brakes are situated by independently operated sources of power; applying said brakes; observing the energy consumed by said sources of power; and adjusting said brakes so that the energy consumed in driving one of said wheels is equal to that consumed in driving the other of said wheels.

' 7. A method of determining the comparative braking efiiciencies of a plurality of brakes on the wheels of a vehicle, said method comprising: simultaneously driving tbe respective wheels by independently operated sources of power; simultaneously applying said brakes; and observing the energy consumed by said sources of power while driving said wheels against the resistance of said brakes.

In testimony whereof, I have hereunto set my hand at Los Angeles, California, this 17th day of September, 1927.

HAROLD W. LANGBEIN. 

